Modular breakwaters have been placed on sea bottoms in the vicinity of eroding shorelines to protect the shorelines from further erosion. However, it has been found that when such breakwaters are employed in areas where they are fully submerged, i.e., where the barrier or reef is placed in about seven to eight feet of water, concerns arise in assembling the breakwater and with toe scour adjacent the beachward face.
Specifically, due to reduced visibility at depths where the barrier would be submerged, which reduced visibility can result from sand suspended in the water, proper alignment of the modules can be difficult. When adjacent modules are improperly aligned, interlocking mechanisms therebetween can be rendered nonfunctional. Accordingly, a further attempt to properly align the modules can be necessary. Therefore, there is a need to provide an interlocking modular breakwater that can be readily aligned, while being submerged.
Further, when an artificial reef is completely submerged some of the wave energy directed at the seaward face can be redirected down the beachward face. This phenomenon creates beachward toe scour, which is not readily apparent from studying shoreline breakwaters where the breakwater is not completely submerged.
The beachward face of typical reef-forming modules is substantially sloped and smooth. It has been found that when these modules are fully submerged, current flows over the modules, and down the beachward face toward the beachward toe of the modules. The current flowing over and down the beachward face of the modules develops a relatively high velocity and causes severe scouring of the sand adjacent to the beachward toe. Such scouring, which could extend ten to twenty feet from the modules, increases the slope of the adjacent sea bottom. As the slope of the sea bottom is increased, the tendency for shoreline erosion increases.
The problem of stabilizing the sea bottom adjacent the beachward face is exacerbated in man-made beaches, i.e., where sand has been pumped in to build-up the beach. These replenished beaches have relatively steep slopes in the area where they meet the natural sea bottom and have a very high tendency toward erosion. In these instances, scouring of the sea bottom adjacent the beachward toe of a submerged reef tends to diminish the erosion protection advantages of the reef and eventually reduces the stability of the artificial reef structure.
Therefore, there is a need to provide a modular breakwater that minimizes or eliminates scouring of sand adjacent to its beachface toe when the breakwater is submerged.